Would you buy a t-shirt for your three-year-old that says 'Slavery gets s**t done'?

Over the weekend outraged shoppers took to Twitter to vent their disgust towards online retailer Amazon for selling t-shirts and bibs for children and babies bearing this shocking slogan. Smiling child models sported the t-shirts saying 'Slavery gets s**t done', with an image of the Egyptian pyramids above it.

Amazon UK has since taken down these product listings made by a third-party retailer.

The company that makes this range of shirts, mugs, tote bags and other products prides itself on being provocative and no doubt many see this as an innocent joke. The problem is that, for the 40 million people trapped in modern slavery today, it's not remotely funny.

For the children who woke up this morning and were forced to break rocks rather than go to school, for the teenagers who are toiling for no money to make the clothes we wear, or the families who are harvesting the coffee we drink, slavery really isn't a laughing matter. At all.

The comments under the Daily Mail's article suggest that this is going to be offensive to left-wing liberals, and that we should just get over it and not by the t-shirt if we don't like it. But for me, the fact that this t-shirt exists at all points to the fact that in the West too many of us have our heads in the sand about what modern slavery really is and what that means for people trapped in it.

I would defy most right-minded people – including those commenting on the Daily Mail – not to want to step in and stop a young boy being tortured with long needles because he tried to run away from the slave-owner who was forcing him to live, sleep and work in one tiny room for no pay. This didn't happen in 1780, it happened recently to a young boy in South Asia who International Justice Mission rescued from a factory making high heels.

Slavery is not confined to the times of the pyramids or the transatlantic slave trade. In fact, there are more people in slavery today than at any other point in history. And one in four modern slaves are children. Today, little children the same age as the child models sporting these t-shirts will have been beaten, starved and sleep deprived as they are forced to work long, back-breaking hours for no money.

It seems so shocking that it can't be real. But it is.

When the Israelites were enslaved by the Egyptians in ancient times, they were certainly getting things done for Pharaoh. Like modern day slave drivers, the slave drivers of ancient Egypt treated the Israelites badly, made them work hard and showed them no pity. But God did not look on the maltreatment of his people favourably and in Exodus 3 he said to Moses: 'I have seen how my people are suffering in Egypt. I have heard them cry out because of their slave drivers. I am concerned about their suffering... And now Israel's cry for help has reached me. I have seen how badly the Egyptians are treating them. So now, go. I am sending you to Pharaoh. I want you to bring the Israelites out of Egypt. They are my people (verses 9-10).

This passage is a central one for IJM and a core motivation behind our work finding and rescuing people in slavery and prosecuting slave-owners and traffickers.

God did not reach down and rescue the Israelites with his own hand in one great miraculous show of power. Instead, he used Moses – a man – who was flawed, like us. He told him to go and set his people free.

Each one of the 40 million people in slavery today were made in the image of God. And God, once more, is calling us to set His people free.

This t-shirt might be incredibly poor taste but my hope and prayer is that disgust will turn to action. That this will provoke more of us to rise up and fight against slavery, helping us get one step closer to ending this great injustice, for good.

David Westlake is chief executive of International Justice Mission. 

Today, IJM launched its Lent campaign asking people to use the 40 days of Lent to help set free the 40 million people in slavery today. Join the fight for Freedom: www.ijmuk.org/lent